A proposed angiographic classification of intracranial arteriovenous fistulae and malformations.

We propose an angioarchitectural classification of intracranial vascular lesions as arteriovenous, arteriolovenous and arteriolovenulous fistulae. In order to validate this classification, 99 intracranial arteriovenous lesions were reviewed in 98 patients. Arteriolovenulous fistulae included 39 isolated brain arteriovenous malformations (AVMs) and 1 AVM associated with a giant arteriovenous fistula (AVF). Arteriovenous fistulae included 8 giant AVFs of the brain, 6 vein of Galen aneurysms and 10 direct caroticocavernous fistulae. Arteriolovenous fistulae included 1 isolated brain AVM, 4 vein of Galen aneurysms and 30 dural AVMs. The angioarchitectural classification has three advantages. It is simple and accurate, with no reference to the congenital or acquired nature of the lesion. It allows separate identification of a special group, the arteriolovenous fistulae. It also indicates the endovascular approach: arteriolovenulous fistulae should be treated via the arterial route only, while arteriovenous and arteriolovenous fistulae can be treated via transarterial or transvenous approaches.